34 is a lot of apples.
That's as many as three tens and four. And that's bad.
For when you need to rid the town of doctors.
So is the 'r in "tri" not rolled?
But I already have 73!
Does the noun not change to indicate that it's a plural?
No, with number noun the noun does not take the plural form. So tri deg pedwar afal (34 apples) but dwi'n hoffi afalau (I like apples)
Why is it not pluralised
Tri deg pedwar o afalau
That pattern is becoming less used nowadays in colloquial Welsh. It is not taught on introductory courses such as this one.